Figure 3. R137Q knock-in mouse embryos have lower levels of cell proliferation and higher levels of cell apoptosis.

(a) Immunohistochemical sections (40×) of E16.5 embryos from R137Q mice showed less Ki67 positive cells. Scale bar: 20 μm. Cells (3 × 10³) were analyzed, and the percentages of positive cells (dark) were calculated and plotted. The data represent the mean ± SD from three independent experiments. (*P < 0.05, Student’s t-test). (b) We measured MEF proliferation rates using continuous cell counting for 6 days. Proliferation of R137Q MEFs was significantly slower than that of WT and WT/R137Q MEFs. The data represent the mean ± SD from triplicate wells (*P < 0.05, Student’s t-test). This experiment was repeated three times. (c) TUNEL analysis was applied to detect apoptosis. More TUNEL-positive cells (dark brown) appeared in sections from R137Q embryos. Cells (3 × 10³) were analyzed, and the percentages of positive cells were calculated and plotted. The data represent the mean ± SD of three independent experiments (*P < 0.05, Student’s t-test). Scale bar: 20 μm. (d) A stronger TUNEL-positive fluorescence signals (green color) was detected in R137Q MEFs. Scale bar: 50 μm. Cells (3 × 10³) were examined at 200× magnification. Percentages of positive cells were calculated and plotted. The data represent the mean ± SD of three independent experiments (**P < 0.01, Student’s t-test).